data representation

Question 1

word size

Answer 1

number of bits a computer’s CPU can process at once
(amount register can hold + manipulate )

Question 2

word

Answer 2

unit of data defining the number of bits that move around a computer from 1 component to another
made of bits

Question 3

possible combinations

Answer 3

2^n
where n = no of bits

Question 4

byte sizes

Answer 4

8 bits = 1 byte
1024 bytes - 2^10 bytes Kilobyte
1024 x 1024 bytes = 2^20 bytes Megabyte
Gigabyte
Terabyte
Petabyte
Exabyte

Question 5

unsigned int

Answer 5

uses all of allocated bits to represent value

Question 6

unsigned int

Answer 6

uses all of allocated bits to represent value

Question 7

largest no. in an unsigned int

Answer 7

2^n - 1
one less than no. of combinations (since 0 is included as one of the values)

Question 8

smallest no in an unsigned int

Answer 8

0

Question 9

sign in binary

Answer 9

left most bit indicates the sign
0= positive 1 = negative

Question 10

two’s complement

Answer 10

soln to adding neg binaries
- make no. binary (add leading 0s)
- reverse (swap 0s and 1s) and add sign
-add 1

check : if pos no + its 2s complement = 0. (ans is 8 bits)

Question 11

from 2s complement to decimal

Answer 11

• reverse 0s and 1s
• add 1
  -convert to decimal equivalent
• add - sign

Question 12

largest no in signed int

Answer 12

2^(n-1) - 1
1 less bit because sign takes 1 bit

Question 13

smallest signed number

Answer 13

-2^(n-1)

Question 14

overflow

Answer 14

try to store a value in a data type that is outside the range data type
cause significant logical errors

Question 15

normalised form

Answer 15

to understand real numbers
0.nnnn x 10^k (all digits moved to fraction part)
ensure no loss of accuracy- 0 can be excluded
nnnn - mantissa k- exponent
signed
lowest exponent: -2^(k-1), highest 2^(k-1) -1
mantissa limited to 9 digits - additional will be truncated/rounded - inaccurate
if too few digits for exponent- overflow